When you’re talking to a customer service rep and they ask if they can call you back because it will take a few minutes to find the information you requested, that’s OK.
What’s not OK is for that rep to not ask for a phone number, especially when said number was neither asked for nor given during the conversation. And it doesn’t inspire much confidence when I asked if she wanted to take my number, which she did, but with a reluctant tone.
So I sit here, completely unsurprised a half hour after being told I would be called back “within 10 minutes”. At least she has my number, should she choose to use it.